Bit and/or stabilizer balling is regarded as a prime technical problem area in oil and gas well drilling. Balling is prevalently defined as the stuck formation material consisting of the drilled materials, also called `drilled cuttings`, or debris that is stuck tight to the surface of the bit and/or stabilizers that are otherwise hard to be removed by the hydraulic circulation of the drilling fluid present. Balling results in detrimental effects to the drilling operations in the form of decreased rate-of-penetration (ROP), frequent trips in and out of the hole causing increased cost of the drilling operation, surge and swab pressure increases, reduced weight-on-bit (WOB) and bore-hole instability.
The causes of bit-balling have been documented in the literature as being manifold. Causes vary from the type of formation that is being drilled, the design characteristics of the drill-bit, the applied down-hole hydraulics, itself consisting of the flow-rate, bit-hydraulic-horsepower (BHHP), formation confining and/or differential pressure, physical and chemical properties of the drilling fluid. However, studying the problem of bit/stabilizer balling in the field can be extremely time consuming as well as expensive. Further, it becomes a great problem to isolate and study the effects of each affecting parameters independently. Hence what is needed in the art is a new technique to study the problem of bit/stabilizer balling, the test procedure of which is quick and the methodology of which is simple yet robust, such that the desired operating conditions can be simulated quickly, providing accurate and repeatable results.